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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Cordysinocan, a novel polysaccharide isolated from cultured cordyceps, has strong effect in stimulating immune responses /

Cheung, Ka Hei. January 2006 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 127-141). Also available in electronic version.
22

The role of mineral surface composition and hydrophobicity in polysaccharide/mineral interactions

Liu, Qi January 1988 (has links)
The interactions of polysaccharides (dextrin, amylopectin and carboxymethyl cellulose (CMC)) with variously modified quartz samples were investigated using floatability, wettability, electrokinetic and adsorption tests, supplemented by conventional titration and infrared spectroscopic studies. The quartz samples were treated either by methylation (rendered hydrophobic), lead coating (introduction of metallic adsorption centres), or both forms of surface modification. The presence of metal ionic sites on a quartz surface played a decisive role in polysaccharide adsorption. The adsorption densities of both dextrin and CMC on lead-coated quartz were both much higher and much more pH-dependent than those on uncoated quartz. The "hydrophobic bonding" of dextrin with mineral surfaces as reported in the literature was not observed with hydrophobic (methylated) quartz. However, if the quartz contained surface lead ionic sites and was also methylated, it adsorbed more dextrin than unmethylated, lead-coated quartz. This was also true for the adsorption of CMC onto similarly modified quartz samples. To obtain a rational understanding of the importance of metal ions in polysaccharide adsorption, studies of the solution chemistry of polysaccharides and metal ions were conducted. CMC co-precipitated with both metal cations and metal hydroxy complexes, (including metal hydroxides), whereas dextrin co-precipitated only with metal hydroxides. Co-precipitation involving either polysaccharide caused a decrease in the solution pH. Dextrin-metal co-precipitation occurred at pH optima of 7.5, 8, 9, 11, and 12 for ferric, aluminum, cupric, lead and magnesium ions, respectively. Infrared spectroscopic studies of the precipitates revealed the elimination of glucose ring deformation, suggesting a chemical basis for the interaction between dextrin and metal hydroxides. The surfaces of sulphide minerals behaved like hydroxide during dextrin adsorption. Since copper and lead hydroxides form over different pH ranges, the pH ranges for optimum adsorption of dextrin on copper sulphides and lead sulphides were different. The results of preliminary flotation tests indicated that dextrin could be utilized in the differential flotation of Cu-Pb sulphides. Small scale flotation tests conducted on synthetic mixtures of chalcopyrite and galena confirmed this point. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate
23

Structural studies of Klebsiella capsular polysaccharides

Yang, Mo-Tai January 1974 (has links)
The genus Klebsiella belongs to the family Enterobacteriaceae. Eighty types of Klebsiella have been serologically classified using the capsular polysaccharides as antigens. In order to understand the chemical basis of serological reactions, structural studies of the capsular polysaccharides from three strains of Klebsiella, namely, K5, K62 and K18 were carried out by means of conventional methods (such as hydrolysis, methylation and periodate oxidation) as well as modern methods (such as circular dichroism (c.d.) for the assignment of the D or L configuration of monosaccharides, gas-liquid chromatography (g.l.c.) and mass spectrometry for isolation and identification of sugar moieties). In the course of the present investigation, p.m.r. spectroscopy at 95° for the assignment of anomeric configurations of the constituent sugars, and Sephadex gel filtration for the separation of a series of acidic oligosaccharides obtained from the partial hydrolysis of polysaccharides for sequential analysis have been developed. The repeating units of K5, K62 and K18 are as follows. The structure of K5 capsular polysaccharide lacks any side chain and is also unusual in affording the first example of a 4,6-0-(l-carboxyethylidene)-D-raannose unit In a natural product. Capsular polysaccharide of K.62 belongs to the prevailing structural pattern so far published in this genus which is composed of a repeating unit involving a single sugar in the side chain with three to four monosaccharides in the backbone. Capsular polysaccharide from K18 is unusua complex in that it consists of two L-rhamnoses in the hexasaccharlde repeat unit which renders the polysaccharide less viscous and acid labile. Finally, an attempted immunological study on K5 is briefly discussed. / Science, Faculty of / Chemistry, Department of / Graduate
24

Studies on bacterial capsular polysaccharides and on a plant gum

Di Fabio, Jose Luis January 1981 (has links)
The structure of the capsular polysaccharides from Klebsiella serotype K60 and K26 have been determined using the techniques of methylation.periodate oxidation,partial hydrolysis, and β-elimination. ¹H- and ¹³C-n.m.r. spectroscopy was used to establish the nature of the anomeric linkages in both polysaccharides and also in the oligosaccharides obtained by the different degradative techniques used. Specific hydrolases obtained from bacteriophages were utilized to degrade two Klebsiella polysaccharides. Larger quantities of oligosaccharide repeating units can be generated in this manner. Two bacteriophages, Ø60 and Ø46,the first one with β-glucosidase activity and the other with β-galactosidase activity, were used to degrade the corresponding polysaccharides according to a new, simplified procedure. The purified gum exudate from Chorisia speciosa (palo borracho) was studied. The results from methylation analysis, β-elimination and partial hydrolysis made possible a tentative assignment for an "average structure" of the gum polysaccharide. / Science, Faculty of / Chemistry, Department of / Graduate
25

Structural studies on Klebsiella capsular polysaccharides

Mackie, Keith L. January 1977 (has links)
Eighty-one serologically distinct strains of Klebsiella bacteria are known. The capsular polysaccharides from these bacteria are their antigenic determinants and in order to help understand the chemical basis of serological differentiation, the detailed chemical structures of these polysaccharides are being determined. The capsular polysaccharides isolated from Klebsiella serotypes K32, K36 and K70 are presented here and have been established using many different chemical techniques. Methyla- tion, partial hydrolysis, periodate oxidation and 3-elimination procedures have yielded analysable subunits of the polysaccharides Extensive use has been made of n.m.r. spectroscopy (¹H and 13 C), mass spectrometry, gas-liquid chromatography and gel filtration in the isolation and identification of the products obtained from the various degradative techniques. The repeating unit structures of K32, K36 and K70 are shown to be as follows: [chemical structures]. Some features of special interest in these structures include: the extreme acid lability of the pyruvate acetal when linking hydroxyls on C₃ and C₄ of a 2-linked L-rharanose residue (K32, K70); the existence of a 3-Lj-rhamnose unit in the structure of K32; and the presence of the pyruvate acetal on only 50% of the linear, six sugar, repeating units of K70. It is also interesting to note that while K70 and K36 have almost the same quantitative composition the chemical structures are markedly different. An efficient means of isolating large quantities of single repeating units of the Klebsiella polysaccharides using glycanase enzymes borne and utilised by specific bacteriophage, is demonstrated. A bacteriophage specific for Klebsiella K32 has been propagated, purified and used to depolymerise K32 polysaccharide. Analysis of the resulting oligosaccharides has shown the glycanase enzyme to be a a-rhamnosidase which cleaves K32 as shown below. [chemical structure] The degradation via bacteriophage is a new area of research and the work described here is only preliminary and as such is presented as an appendix. / Science, Faculty of / Chemistry, Department of / Graduate
26

Modelling of polysaccharide-chiral stationary phase

Thor, Waygen 08 November 2019 (has links)
Cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) is among the most common stationary phases used in chiral separation column. Nevertheless, there is no crystal structure of CDMPC reported yet for reference. Modelling studies of CDMPC so far have been based on the basis of the parameterized structure of the dry crystalline structure of cellulose tris(phenylcarbamate) (CTPC) predicted in late 80s. Solvent effect was not considered explicitly in those studies. In 2016, Okada et al. reported that the number of monomeric units of CDMPC would influence the structure of the chiral stationary phase (CSP), and hence the chiral recognition ability. However, most of the previous modelling studies ignored the chain-length effect and considered CDMPC with at most twelve residues. In this study, the effects of explicit solvent and number of residues on CDMPC are investigated specifically. Modelling of two chain lengths (9-mer and 18-mer) of CDMPC using molecular simulation in both implicit and explicit solvent environments were performed. Predicted elution order of selected enantiomers on 18-mer CDMPC agrees better with experiments. Design principles of polysaccharides-CSPs were discussed based on this study.
27

Some South African red seaweed polysaccharides

Clingman, Abraham Lionel January 1958 (has links)
Algae have been classified by botanists into four large groups: the Chlorophyceae or green algae, the Phaeophyceae or brown algae, the Rhodophyceae or red algae, and the Cyanophyceae or blue-green algae. The polysaccharides which are extracted from marine algae may be differentiated into reserve polysaccharides, analogous to starch in land plants, and into structural polyrsaccharides, analogous to cellulose in land plants. Laminarin from brown seaweeds and Floridean starch from certain red algae are reserve polysaccharides while algihates (from brown seaweeds) and carrageenin and agar (from red seaweeds) are structural polyrsaccharides. The most common encountered algal polycysaccharides, besides alginic acid, are agar and carrageenin. These are salts of sulphate esters of polysaccharides which contain D-galactose. Agar and carrageenin mucilages are obtained by aqueous extraction from certain red seaweeds of the class Florideae. Agar is extensively used in the meat canning and confectionery trades where it has to a very large extent replaced gelatin. Nearly all the South African production of agar is used in this way. Carrageenin is used in brewing as a clarifying agent, as a stabilising agent in cocoa and in a large number of pharmaceutical products.
28

Deoxy and branched-chain sugars.

Hanessian, Stephen January 1960 (has links)
No description available.
29

Structural studies in certain animal polysaccharides /

Sutherland, Gordon January 1953 (has links)
No description available.
30

Antitumor activities of polysaccharides extracted from sclerotium of polyporus umbellatus.

January 2004 (has links)
Cheng Chiu-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 112-123). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.I / ABSTRACT --- p.III / 摘要 --- p.V / LIST OF FIGURES --- p.XII / LIST OF TABLES --- p.XV / LIST OF ABBREVIATIONS --- p.XVII / Chapter CHAPTER 1 --- LITERATURE REVIEW --- p.1 / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.2 --- Cancer Treatment Modalities --- p.3 / Chapter 1.3 --- Cancer Immunotherapy --- p.4 / Chapter 1.3.1 --- Immunomodulation --- p.4 / Chapter 1.3.2 --- Conventional immunotherapy --- p.5 / Chapter 1.3.2.1 --- Active immunotherapy --- p.5 / Chapter 1.3.2.2 --- Passive immunotherapy --- p.5 / Chapter 1.3.3 --- Novel immunotherapy --- p.8 / Chapter 1.3.3.1 --- Natural Products from Chinese Medicinal Herbs as BRMs --- p.9 / Chapter 1.4 --- Antitumor polysaccharides from Mushrooms --- p.10 / Chapter 1.4.1 --- Composition of mushroom antitumor polysaccharides --- p.10 / Chapter 1.4.1.1 --- β-glucan --- p.10 / Chapter 1.4.1.2 --- Heteroglucan --- p.11 / Chapter 1.4.1.3 --- Glycan and polysaccharide-protein complexes --- p.11 / Chapter 1.4.2 --- Antitumor polysaccharides from Polyporaceae mushrooms --- p.14 / Chapter 1.4.2.1 --- Lentinan from Lentinus edodes --- p.16 / Chapter 1.4.2.2 --- Maitake from Grifola frondosa --- p.17 / Chapter 1.4.2.3 --- Polysaccharides from Ganoderma lucidum --- p.18 / Chapter 1.4.3 --- Extraction and purification of Polysaccharides from Mushrooms --- p.19 / Chapter 1.4.4 --- Chemical modification --- p.20 / Chapter 1.5 --- Polyporus umbellatus (Zhuling) --- p.20 / Chapter 1.5.1.1 --- Nutritional Contents --- p.21 / Chapter 1.5.1.2 --- Medicinal properties --- p.21 / Chapter 1.6 --- The Objective of the Present Project --- p.23 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.25 / Chapter 2.1 --- Extraction --- p.25 / Chapter 2.1.1 --- Hot-water extraction of crude Polyporus umbellatus polysaccharides --- p.25 / Chapter 2.1.2 --- Cold-alkaline extraction of crude Polyporus umbellatus polysaccharides --- p.26 / Chapter 2.2 --- Purification of crude Polyporus umbellatus polysaccharides --- p.29 / Chapter 2.2.1 --- Preparation of DEAE-cellulose ion exchange column --- p.29 / Chapter 2.2.2 --- Fractionation of hot-water soluble crude polysaccharide (PU) --- p.29 / Chapter 2.3 --- Characterization of Polyporus umbellatus Polysaccharides --- p.30 / Chapter 2.3.1 --- Carbohydrate content determination --- p.30 / Chapter 2.3.2 --- Gas chromatography (GC) --- p.31 / Chapter 2.3.3 --- Protein content determination --- p.32 / Chapter 2.3.4 --- Uronic acid content determination --- p.33 / Chapter 2.3.5 --- High Performance Liquid Chromatography (HPLC) --- p.34 / Chapter 2.4 --- In vivo Antineoplastic Assay --- p.35 / Chapter 2.4.1 --- Animals --- p.35 / Chapter 2.4.1.1 --- BALB/c mice --- p.35 / Chapter 2.4.1.2 --- Athymic BALB/c mice --- p.36 / Chapter 2.4.2 --- Maintenance of cell lines --- p.36 / Chapter 2.4.2.1 --- Murine sarcoma 180 --- p.36 / Chapter 2.4.2.2 --- Human breast cancer cell line (MCF-7) --- p.37 / Chapter 2.4.3 --- S-180 tumor inoculation model using BALB/c mice --- p.37 / Chapter 2.4.4 --- MCF-7 tumor inoculation model using athymic nude mice --- p.38 / Chapter 2.4.5 --- Assay of antineoplastic activity with S-180 --- p.38 / Chapter 2.4.6 --- Assay of antineoplastic activity with MCF-7 --- p.39 / Chapter 2.4.7 --- Body weight change --- p.40 / Chapter 2.5 --- In vitro anti-proliferation assay --- p.41 / Chapter 2.5.1 --- Cell lines --- p.41 / Chapter 2.5.1.1 --- Maintenance of cell lines --- p.41 / Chapter 2.5.2 --- Assay of anti-proliferation with cancer cell lines --- p.42 / Chapter 2.5.2.1 --- Cytotoxicity assay on suspensions of cancer cells --- p.42 / Chapter 2.5.2.2 --- Cytotoxicity assay on adhesive cancer cells --- p.42 / Chapter 2.5.2.3 --- Cytotoxicity assay on normal cells --- p.43 / Chapter 2.5.3 --- Trypan blue exclusion method --- p.43 / Chapter 2.5.4 --- MTT assay --- p.44 / Chapter 2.6 --- Cytokine determination --- p.45 / Chapter 2.6.1 --- Treatment of mice --- p.45 / Chapter 2.6.2 --- Enzyme-linked immunosorbent assay (ELISA) for TNF-a production --- p.46 / Chapter 2.6.3 --- Analysis of mouse cytokine array --- p.47 / Chapter 2.6.3.1 --- Process of blocking and incubation --- p.47 / Chapter 2.6.3.2 --- Process of cytokine detection --- p.48 / Chapter 2.7 --- Statistical Analysis --- p.49 / Chapter CHAPTER 3 --- RESULTS --- p.50 / Chapter 3.1 --- Extraction of Polyporus umbellatus polysaccharides (PU) --- p.50 / Chapter 3.1.1 --- Percentage of Yield in extraction of crude PU extracts --- p.50 / Chapter 3.1.2 --- Percentage of yield in fractionation of PU fractions --- p.51 / Chapter 3.2 --- Chemical characterization of PUW fractions --- p.55 / Chapter 3.2.1 --- Carbohydrate and protein contents of puw fractions --- p.55 / Chapter 3.2.2 --- Relative content of monosaccharides and uronic acid in PUW fractions --- p.55 / Chapter 3.2.3 --- Infrared spectra of PUW fractions --- p.59 / Chapter 3.2.4 --- Molecular weight estimation of PUW fractions --- p.59 / Chapter 3.3 --- In vitro anti-proliferative assay --- p.64 / Chapter 3.3.1 --- Anti-proliferative effects of PU fractions on suspension cancer cell lines --- p.64 / Chapter 3.3.2 --- Anti-proliferative effects of PU fractions on adhesive cancer cell lines --- p.64 / Chapter 3.3.3 --- Anti-proliferative effects of PU fractions on normal cell lines --- p.65 / Chapter 3.4 --- In vivo antineoplastic assay --- p.73 / Chapter 3.4.1 --- S-180 tumor inoculation model using BALB/c mice --- p.73 / Chapter 3.4.1.1 --- In vivo antineoplastic effect of crude extracts - PUW and PUAL --- p.73 / Chapter 3.4.1.2 --- In vivo antineoplastic effect of PUW --- p.73 / Chapter 3.4.1.3 --- In vivo antineoplastic effect of PU60 and PU80 --- p.78 / Chapter 3.4.1.4 --- In vivo antineoplastic effect of PU60a and b --- p.81 / Chapter 3.4.2 --- MCF-7 tumor inoculation model using athymic nude mice --- p.81 / Chapter 3.4.2.1 --- In vivo antineoplastic effect of PU60b --- p.81 / Chapter 3.4.3 --- Identification of cytokines in the serum from healthy BALB/c mice using mouse cytokine array system --- p.89 / Chapter 3.4.4 --- Effect of PU60b on TNF-α generation in healthy BALB/c mice studied with ELISA. --- p.93 / Chapter 3.4.5 --- Effect of PU60b on TNF-α generation in S-180 tumor bearing mice studied with ELISA --- p.93 / Chapter CHAPTER 4 --- DISCUSSION --- p.96 / Chapter 4.1 --- Extraction and Isolation of polysaccharide fractions --- p.96 / Chapter 4.2 --- Chemical characterization of PUw fractions --- p.97 / Chapter 4.3 --- In vitro anti-proliferative effect of PU fractions --- p.99 / Chapter 4.4 --- In vivo antineoplastic assay of PU fractions --- p.101 / Chapter 4.4.1 --- S-180 solid tumor model using BALB/c mice --- p.101 / Chapter 4.4.2 --- MCF-7 tumor in vivo model using athymic nude mice --- p.104 / Chapter 4.5 --- Estimation of Immunomodulatory properties of PU60b --- p.106 / Chapter 4.5.1 --- Identification of cytokines in serum from healthy BALB/c mice --- p.106 / Chapter CHAPTER 5 --- CONCLUSIONS --- p.110 / REFERENCES --- p.112

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